This invention generally relates to a pressure control valve assembly for use in vehicle braking systems and more particularly to improvements in a pressure control valve assembly for controlling the fluid pressure in wheel brakes of the split braking system.
For instance, in order to reduce the increase of the hydraulic brake pressure in rear wheel brakes with respect to the increase of the hydraulic pressure in the front wheel brakes or brake master cylinder there has been proposed a pressure control valve assembly for avoiding locking of the rear wheel. When the brake system has separate pressure sources such as a split master cylinder, it is necessary to control the brake pressure in each independent pressure line.
The conventional pressure control valve assembly for use in split braking system is provided with means for compensating for hydraulic failure in one of the pressure lines by disabling or by-passing the control valve operation in the other pressure line.
These valve assemblies are not free from other problems, i.e., the construction thereof is complicated and they are large in size so that it is difficult to install the control valve assembly in the limited space available in vehicles.